1,7

RECORD transform of a(n) is A140475 (union of number 1 and primes >= 5).

Sequence of numbers n such that a(n) = floor(antisigma(n) / n) = A046022.

Sequence of numbers n such that a(n) = a(n+1) = A244666.

Table of n, a(n) for n=1..74.

a(n) = A244327(n) - A244328(n) for n >= 7.

For n = 10; a(10) = floor(A024816(10) / A000203(10)) = floor(37 / 18) = 2.

(MAGMA) [Floor(((n*(n+1)div 2)-SumOfDivisors(n)) div (SumOfDivisors(n))) : n in [1..1000]]

Cf. A000203, A000217, A024816, A046022, A244327, A244328, A244666.

Sequence in context: A240388 A049823 A143775 * A003165 A158379 A122838

Adjacent sequences: A244326 A244327 A244328 * A244330 A244331 A244332

nonn

Jaroslav Krizek, Jul 08 2014

approved